Improvement in the manufacture of sheet-iron hollow ware



of this more refractory metal.

IINITED STATES PATENT OFFICE.

JOHN yGREY AND JOHN D. GREY, OE PITTSBURG, PENNSYLVANIA, ASSIGN- ORS TO THEMSELVES AND THOMAS GREY, OF SAME PLAGE.

IMPROVEMENT IN THE MANUFACTURE OF SHEET-IRON HOLLOW WARE.

Specification forming part of Letters' Patent N0. 33,446, dated May 5, 1863.

To all whom it may concern:

Be it known that we, JOHN GREY and JOHN D. GREY, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in the Manufacture of Sheet-Iron Hollow Vare'; and we do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a planer top view of` the die used by us. Figs. 2, 3, and tare vertical sec tions of our dies, each with its forcer or plunger raised, showing in dotted lines the shape and position of the metal to be operated upon, and in black lines the result produced by the forcing down of the plunger, each of these figures exhibiting a different stage in the operation of making sheet-iron hollow ware. Pig. 5 is a vertical section of the plunger and mold in which the article, partially shaped by a succession of dies, is finally reduced to the required conformation.

In the several figures like letters of reference denote similar parts.

There are various modes in use for constructing articles of hollow ware out of a single piece without scam from the more ductiley metals, especially brass .and copper, such as spinning'by the pressure of a tool on the metal against a former, drawing out the metal by forcing it gradually into or through a more and more contracted space, and swaging or stamping it into shape by compressure between a male and female die p resentingthe exact shape ofthe article to be made and its counterpart, and still other methods consisting of a combination or combinations of one ormore of these methods. Sheet-iron is, however, not so ductilc as copper and brass, and it might readily be supposed to be impossible to form articles of any considerable degree of concavity in one piece out of single sheets Ve have nevertheless accomplished this result by the use of the peculiar kinds of dies yhereinafter described, and make sauce-pans, wash-basins, and even kettles of the shape and size of brass kettles out of disks of sheet-iron by a gradual swaging or stamping process, whereby the required conformation in given little by little at each stage of the operation, acting on a fresh part of the metallic disk, and not, as is common in swaging, subjecting those parts formed in the earlier stages of the operation to the repeated action of the dies.

In stamping or swaging brass kettles it is not uncommon to have a series of dies or matrices, the iirst one very shallow, but of the exact shape of the bottom of the kettle, the second one of the same shape at bottom, but of greater depth or higher in the sides, the third one of the same shape as the second, but still deeper, and each having a corresponding male die a counterpart ofthe shape of its matrix or female die, so that by the first operation with the, shallowest die the bottom is formed, in the second the sides are raised higher and the bottom receives a further blow, and so on in succession, the bottom of the kettle being acted upon as often of there are stages in the operation. The effect of this is to reduce the thickness of the bottom part of the kettle, and render it unnecessarily weak at the part where it ought to be the strongest. By our method, which is principally designed and peculiarly adapted to operate upon sheet iron, all our female dies (except the finishing die) are without any bottom, so that the bottom of the kettle or other article to be made is not pressed between dies nor shaped until the very last stage of the operation, whereby it remains not only as strong as but stronger than the other parts of the kettle or other article of hollow ware.

To enable others skilled in the art to construct and use our improved dies for making iron hollow ware, we will proceed to describe our invention more precisely.

In the drawings, a is a heavy block of castiron or other metal having a circular cavity, b, through it, the axis of which is perpendicular, and itsdiameter equal at least to the diameter ofthe largest kettle or other article to be made upon it. At the upper side ofthis block a, around the cylindrical cavity b, is a recess of sufficient depth and width to receive the dies c d e, Snc., the depth ofthe recess being equal to the thickness of these dies, and its width such as to give the diesagood bearing on the block,

' in it.

to which they are attached firmly by the screws s s. Each of these dies c d e is a circular block of steel fitting into the recess in the block a, and its under faceproiecting over the inner edge of the block toward its center, the first die, c, in the series projecting the farthest, (see Fig. 2,) the second die, d, projecting not so far, (see Fig. 3,) and so on, each die in the series proj ccting a less distance beyond the face ot' the cavity in theblock a, or, in other words, the die c having a smaller cavity or bore than d, and the die d a smaller cavity than e, and so on through the series, which may be two, three, or more, according to the required size and depth of the articles to be manufactured.v The dies c d c (as before stated) have no bottom, and each is about the same depth or thickness. Their cavity or bore is circular, but of greaterdiameter on its upper than on its lower face, so that the sides of' the cavity in cach are flaring or inclined at a greater or less angle to its axis, according to the shape to be given to the metallic disk to be operated upon. Each die c d c, die., has a corresponding forcer or male die, j" g h, (made of an alloy of' zinc and lead, with a little autimony,) the shape of which is a counterpart of its die, with a flange projecting a short distance horizontally above the lower part of the forcer, so as to press down the sheet at its circumference and prevent, as much as possible, the buckling of' the metal. p

The mold or die shown in Fig. 5 is a solid block, t', having a bottom, and its cavity being the exact shape of' the article tobe finished It has a plunger crmale die, 7.a, of corresponding configuration. This die and former arcvery similar to those employed in the swaging or stamping process as ordinarily practiced.

The operation of making articles of iron l1ollow ware with our improved dies is as follows:

- The die e, which has a cavity ofthe smallest diameter in the series being secured in its place in the block bythe screws or bolts s s, a circular disk or sheet of iron is placed horizontally on top of the die and concentrically therewith. The male die or forcer is then struck or dropped down on the sheet, the

blows being repeated until the sheet is forced to assume a counterpart of' the shape of the forcer f, as shown in Fig. 2. The flange around the forcer c keeps down that portion of the disk which is not to be dished or forced into the die c, and prevents in a great measure the buckling or wrinklinga of the outer part of the disk.

It will be observed by comparing Figs. 2 and 5 that the smallest diameter of' the first forcer, j', is greater than the diameter of the bottom of the kettle or other article designed to be made, the purpose of which is that the central portion of' the disk, which is to form the bottom of the kettle, may receive no strain during the process of shaping the sides, it being important in the making of hollow ware of'sheet-iron that the edge of thebottom should not be thinned or cracked, as it would probably become if the the bottom of' each of the forcers were of the ultimate shape of the bottom of theikettle and struck the center ofthe disk at cach stroke during the process of manufacture. The disk thus partially shaped by the first forcer, f, and die c is removed, and the die d being substituted in the block a, the disk is placed on it with the concave portion projecting downward, but not touching the sides of the cavity of the second die, d, as seen by dotted lines in Fig. 3. The forcer g is then struck or dropped upon the disk within the die d, and the blows are repeated until it assumes the shape of the cavity of the die. In this second process, and in cach subsequent process, (excepting the final one,) the forcer does not reach to the bottom of the ccncavity formed by the first die and forcer, but acts upon and shapes that portion of the disk immediately around the ccncavity formed by the preceding operation,lengthening the sides and deepening the ccncavity of' the kettle or other article being formed, but not acting a second time upon that portion of the disk previously acted upon by the dies and forcers. This process is repeated, as shown in Fig. 4, with a die, c, of' greater diameter than that previously used, and a forcer, h, of corresponding shape, and is carried on with a succession of dies and forcers of gradually-increasing diameter, until the required size and depth of' ccncavity is attained. The kettle or other article is then removed to the finishing-die t, which is a solid block of the exact shape which it is desired to give to the article when finished.

The general shape of the partially-finished article is similar to that which is to be given to it in the finishing die, except that the bottom is of too great diameter, and is not of the proper sh apc, and the sides having been formed in stages and never acted upon as a whole, require to be smooth. All thisis done by the finishing-die t and plunger k, between which the kettle is 'finally shaped and smoothed by repeated strokes4 of the plunger 7c.

By the process just described of forming the articles in successive stages, gradually increasing` the depth, beginning near, but not at the bottom, with the use of shallow bottcmless dies, with fiaring sides and shallow plungers of corresponding shape, we are enabled to make various articles of hollow ware out of disks of' sheet-iron, which heretofore havebeen made in pieces riveted or welded together.

Having thus described our improvement, what we claim as our invention is- Making articles of seamless hollow ware out of sheet-iron, in the manner substantially as described, by the use of a succession of shallow bottomless dies having ilaring or curved sides, each die in the series being` of greater l GREY and JOHN D. GREY, have hereunto set diameter than the last, with foroers of correour hands.

spending shape and depth, whereby the art- I oies are gradually shaped from a fiat disk by l successive stages, the bottom or central part ftnessesz of the disk being last shaped. v l A. S. NICHOLSON, In testimony whereof we7 the said JOI- IN W. BAKEWELL.

JOHN GREY. JOHN D. Gaan 

